Envelope manufacturing machines which fold the closure, side and bottom flaps or panels of envelope blanks are well known in the prior art. Such machines which manufacture such envelopes on a production line basis are also well known, including such apparatus which automatically applies adhesive or gum to predetermined portions of the envelope blank during the manufacturing process and cuts windows in the envelope blank.
While it is known to make envelopes and apply adhesives to various flaps and other portions of the envelope in a continuous production line system, if the gum is incorrectly applied to the predetermined areas of the envelope, then the envelope will not function as designed. Such will in turn negatively affect the basic use of the envelope as well as cause problems with inserting equipment and postal sorting equipment. Traditional ways to validate the correct positioning of gum and the window at predetermined points on the envelope blank have been visual inspection, holding the envelope to a template manually measuring portions of the envelope or the like. Such methods rely on an interpretation of measurement apparatus and standards and specifications and requires a multiplicity of tools and is time consuming and subject to error.
There is a need for an apparatus and process which may be utilized by an operator to more quickly and easily validate that window and the gum exist and is in the proper position and length and which is reliable.